The clock is ticking

Found this interesting item on John Jamison's ImagiLearning blog:                                    

There is something about the human brain that causes it to begin to refocus every 10 minutes. So after doing your best for 9 minutes, spend the next 60 seconds doing something to re-capture the brain's attention, to 'hook' it into sticking around for the next 10 minutes. If you lecture for 60 minutes...or create online courses...chunk them into 10 minute 'modules' divided by a 60 second "hook"...something that will cause the learners' brains to say, "Say what?" This buys you another 10 minutes.

 Don't know what research this comes from, but it's interesting enough to try out.  I'll watch in my next training program to see if folks get restless in 10-minute intervals.  Anybody notice this in their own classroom work?